1. Field of the Invention
The present invention relates in general to automotive air cooling systems, and more particularly to a refrigerant over-charging checking system for preventing a closed circuit refrigeration air cooling system from being over charged with the refrigerant.
2. Description of the Prior Art
In order to charge or recharge the closed circuit refrigeration air cooling system with refrigerant, a so-called service valve has been mounted in a conduit of the system. Upon the requirement for charging, a charging hose from a refrigerant container is coupled with the service valve, and then the associated compressor is driven at a relatively low speed for a certain time. Usually, this charging work is carried out while observing the condition in the system through a sight glass mounted to the conduit (or a liquid tank). However, this work sometimes induces overcharging of the system due to the inherently difficult task of detecting the critical state of the refrigerant through the sight glass. Overcharging of the system causes poor function of the same, and thus it should be avoided.